[3][4] Kellett was founded in 1976 by parents who wanted a high-quality, British-style education, rich in the Arts and Sport.

[5] Originally called Starters, the school was led by Joanne Elliott and her family, working with the first Principal, Vivienne Steer.

The school's first two classes were made up of British, American, Australian, Chinese, Japanese, Korean, Indian, Pakistani, Iranian, Norwegian, and Swedish children.

[7] In 1980, the school moved to a purpose-built facility in Wah Fu overlooking Kellett Bay.

In 2018, Kellett was awarded membership of the Independent Association of Preparatory Schools (IAPS) and the Headmasters’ and Headmistress’ Conference (HMC).

She was awarded an OBE for her services to education and the British community in Hong Kong in the Queen's Birthday honours list that year.

In 2023, Diana Vernon join Kellett as temporary Principal & CEO, she was most recently the Educational Advisor to the Kellett Board and has served as Head of City of London School for Girls and Principal and CEO of Methodist Ladies College, Melbourne.

[11] There are currently 1,382 pupils on roll, aged four to 18 years, making Kellett similar in size to other all-through international schools in Hong Kong.

[14] All students throughout the school take the award winning[15] Positively Kellett course,[16] a lesson designed to evaluate properties such as public speaking, and gives knowledge about the global goals, character strengths and anti-bullying.

[21] The Pok Fu Lam premises includes a large multi-use auditorium, a gymnasium, library, a fully equipped science lab, dance and drama studio, ICT suite, language lab, SEN learning support base, music rooms, art studio and a children's bookshop.

The "covered area" provides a large indoor space for the Reception and Year 1 children.

The Kowloon Bay campus welcomed its first cohort of Prep and Senior students in September 2013.